Shearing mechanism for tufting machines



June 13, 1967 J. M. SMITH SHEARING MECHANISM FOR TUFTING MACHINES FiledFeb. 5, 1965 lNvENToR, JAMES M. SMITH ww/I BY ATTORNEYS United StatesPatent O 3,324,812 SHEARING MECHANISM FOR TUFTING MACHINES James M.Smith, West Point, Ga., assigner, by mesne assignments, to CallawayMills Company, La Grange,

Ga., a corporation of Georgia Filed Feb. 5, 1965, Ser. No. 430,706 8Claims. (Cl. 112-79) This invention relates to tufting machines and ismore particularly concerned with a shearing mechanism for tuftingmachines.

In U.S. Patent No. 3,089,442 there is disclosed a pneumatic tuftingmachine which is suitable for producing a variety of tufted products.The present invention relates to a shearing -mechanism for thispneumatic tufting machine, the shearing mechanism employing overlappingreciprocating blades which ride against a shear plate disposed beneaththe backing material for shearing the backing material and throughapertures in the shear plate.

It is, therefore, an object of Ithe present invention to provide an'inexpensive, durable and eiiicient shearing mechanism for operation inconjunction with a tufting machine for evenly and effectively shearingthe ends of loops of yarn sewn in a backing material by the tuftingmachine.

Another object of the present invention is to provide a shearingmechanism for a tufting machine, in which the blades therefor are evenlybiased, self sharpening, are capable of operating without adjustment forextended periods of time and may be individually removed, if it is foundnecessary to sharpen the blade.

Another object of the present inven-tion is to provide, in a shearingmechanism, an arragement of side-by-side blades for shearing loops ofyarns, wherein the danger of the yarns becoming wedged between adjacentblades is reduced to a minimum.

Other objects, features, and advantages of the present invention willbecome apparent from the following description when taken in conjunctionwith the accompanying drawings wherein like `characters of referencedesignate corresponding parts throughout the several views, and inwhich:

FIG. 1 is a fragmentary perspective view of a portion of a tuftingmachine containing the shearing mechanism of the present invention;

FIG. 2 is a fragmentary side elevational view of that portion of themachine shown in FIG. l, the machine being illustrated as in the processof producing cut pile tufts in a backing material.

FIG. 3 is a cross-sectional view taken substantially along line 3 3 inFIG. 2;

FIG. 4 is a cross-sectional view taken substantially along line 4-4 inFIG. 3.

Referring now in detail to the embodiment chosen for the purpose ofillustrating the present invention, it being understood that, in itsbroader aspects, the present invention is not limited to the exactdetails herein depicted, the tufting machine on which my shearingmechanism is operative is of the type illustrated in U.S. Patent No.3,089,442, the tufting machine including a hollow needle bar which isreciprocated in the usual way and carries a plurality of hollow needles11 The hollow needles 11 project downwardly from the needle bar 10 andare arranged in two or more parallel transverse rows over a backingmaterial B. The needles 11 'are staggered with respect to each other sothat adjacent needles 11 are transversely spaced and offset inrespective rows, as illustrated in FIG. 1.

Air, or some other fluid, under pressure supplied to the Ihollow needlebar 10 passes in downward paths ICC through all needles 11 so `as toemerge, -as a downwardly directed stream, out of the beveled dischargeends 12 of the needles 11. Yarns Y, supplied in prescribed amounts, by ayarn control mechanism (not shown) pass through the needles 11 and areurged by the streams of air out of ends 12 to the full extent permittedby the yarn control mechanism.

Below the needle bar 10 is a transversely extending presser footIassembly 15 which is usually supported in -a stationary position fromthe orosshead or crank case (not shown) of the machine. The presser footassembly 15 includes a horizontally disposed presser foot 16 and aninclined -slide plate 17 integrally joined along a common edge 18 andangularly disposed with respect to each other so that the slide plate 17projects upwardly and rearwardly from the presser foot 16.

The presser foot 16 is provided with a plurality of apertures or holes19, aligned respectively with needles 11 and through which the needles11 project upon downward movement of the needle bar 10. The common edge13 is immediately rearward of the path of travel of the rear row ofneedles 11.

Spaced slightly below the presser foot 16 are a plurality of parallellongitudinally extending vanes 20. The spaces between the vanes 20 arealigned with the holes 19 of the pressor foot 11 so that, at the bottomdead center position of needles 11, the ends 12 of needles 11 afterpassing through the Ibacking material B are disposed between adjacentvanes 20. Vanes 20 are supported in cantilever fashion -by a needleplate 21, the front portions of the vanes 26 being embedded in the rearedge portion of the needle plate 21. In turn, the needle plate 21 isdisposed on the upper surface of and is supported by the front iiange 22of the cross ibed of the machine.

The opposed rear flange 23 of the cross bed of the machine supports aforwardly extending flat shear plate 25 parallel to the presser foot 16and the plane of vanes 20. The forward portion of shear plate 25 extendsbeyond the forward edge of liange 23 and is disposed below the vanes 20.Shear plate 25 is below the extremity of penetration of needles 11 andis provided with a plurality of apertures 26 which are respectivelyaligned with needles 11 so that yarns Y, discharged from the ends 12 ofthe needles 11, will be directed toward apertures 26 and be receivedtherethrough, provided the loops L of yarns Y are suiciently long.

Rearwardly of apertures 26, the flange 23 carries an upwardly andrearwardly inclined deector plate 27 which is disposed approximatelyparallel to the slide plate 17 of the presser foot assembly 15. It willbe understood that backing material B, seen in FIG. 2, is fed by feedrollers (not shown) in a rearward direction longitudinally over theneedle plate 21 and the vanes 20, passing -beneath the presser foot 16and thence up the inclined passageway, dened by the slide plate 17 andthe deector plate 27, to the discharge rollers (not shown).

Below the shear plate 2S, a knife reciprocating mechanism 3d isprovided. The reciprocating mechanism 30 includes a plurality ofupstanding rocker farms, such as arm 31, which carry, at their upperends, a transversely extending angle iron. All rocker arms 31 are movedback and forth, forwardly and rearwardly, in timed relationship to thereciprocation of the needles 11. The angle iron carried by the rockerarms 31 immediately below the shear plate 25 has an upwardly andforwardly inclined block carrying b-ase flange 32 and an upwardly andrearwardly inclined stop flange 33. The flanges 32 and 33 are joinedalong a common edge 34.

Carried by the base ange 32 are a plurality of spaced side-by-sidejuxtaposed rectangular knife carrying blocks 35 which yare secured inplace on the upper surface of the base flange 32 by bolts 36 which passupwardly through slots 37 in flange 32 and are respectively threadedlyreceived in blocks 35. The slots 37 are elongated perpendicular to thecommon edge 34 for permitting limited individual adjustment of theblocks 35 toward or away from stop or flange 33.

According to the present invention, each block 35 is provided with aforwardly opening slot 3S extending from one side 39 to the other, 40,of block 35 through the central and forward portions of the block 35,the slot 38 being inclined with respect to the parallel upper and lowersurfaces 41 and 42 of the block 35. A set screw 43, seen in FIG. 2,passes from the top or upper surface 41 of each block 35 for removablyretaining in place, by its rear lportion, a knife or blade 45.

Each knife or blade 45 is formed from an initially rectangular strip ofspring steel. Thus, each blade or knife 45 has a at upper or top surface46; a flat lower or bottom surface 47 parallel to the upper surface 46;straight side edges 48 and 49, which are parallel to each other, and astraight rear yedge 50 perpendicular to and extending between the endsof the side edges 48 and 49.

The front or cutting edge 51 of each knife or blade 45 is a straightedge, angling across the forward end of blade 45. Thus, side edge 48 ofeach blade 45 is longer than the side edge 49 thereof so that thecutting edge 51 intersects side edge 48 at an acute angle or point 53and intersects side edge 49 at an obtuse angle or point 54. Furthermore,the front or cutting edge 51 is formed by bevelling the front portion ofknife or blade 45 to provide an inclined front of beveled surface 52disposed at an obtuse angle with respect to the bottom surface 47 whilebeing disposed at an acute angle with respect to the upper surface 46.Thus, the cutting portion of the cutting edge 51 is adjacent the upperor top surface 46 of each blade 35.

When a knife or blade -45 is received in its associated block 35, i.e.,when the end portion of blade 45 which is adjacent the rear edge of 50,is inserted into the slot 38 of its associated block 35, the blade 45 isslightly canted about its longitudinal axis to dene an acute tilt anglewith respect to the base flange 32, so that the shorter side edge 49 isslightly higher than the longer side edge 48 and therefore closer to theshear plate 25. The distance from the block 35 to the flat bottomsurface of the shear plate is substantially shorter than the length ofthe blade 45. Furthermore, the blade 45 is carried generally flatwisewith respect to the shear plate 25 and so that it extends upwardly andforwardly toward the outer or bottom surface of shear plate 25 with itsfront or cutting edge 51 engaging and riding upon the outer or bottomsurface of the shear plate 25 throughout the length of cutting edge 51.

In its cutting position, each blade 45 is held at an inclined upward andforward angle, so that the blade 45 is flexed toward the shear plate 25with its upper surface 46 convexed and its lower surface is concaved.The blade 45 is so angled by the slot 38 that an upward biasing pressureis exerted by the blade 45 on its cutting edge 51 for biasing thecutting edge 51 at all times against the outer or lower surface of theshear plate 25, throughout the length of the cutting edge 51.

As best seen in FIG. 3, the transverse width of each knife or blade 45,is, from edge 4S to edge 49, greater than the width of block 35.Therefore, the edge portions of knife or blade 45 protrude outwardly4beyond sides 39 and 40 of its associated block 35. Furthermore, thedistance between centers of adjacent blocks is less than the width of ablade 45. Also, the tilt angle of adjacent blades 45 is suicient for theside edge 48 of one blade 45 to overlap the side edge 49 of an adjacentblade 45.

When all blades 45 are in place in their blocks 35, the blades 45 extendtransversely across the shear plate 25 so as to present a continuity ofcutting edges 51 slightly wider than the width of the row or rows ofapertures 26 and generally transversely parallel to the rows ofapertures 26.

The blade reciprocating mechanism 30 is so arranged and constructed thatit moves the base flange 32 backward and forward in timed relationshipto the reciprocation of the needle bar 10 and needles 11. This actionslides the cutting edges 51 of all blades 45 along the bottom surface ofshear plate 25 simultaneously across the apertures 26 in a back andforth movement so as to dispose the cutting edges 51 rst on one side ofthe rows of apertures 26 during a portion of one cycle of the machineand then on the other side of the rows of apertures 26 during anotherportion of the cycle.

Preferably, the blades 45 complete their cutting or shearing actionafter the loops L have been extended to the full extent of theirformation. In this way, a smooth cut transverse to the legs of the loopsis provided so that a bight portion of each loop is severed, providedthe loop is suiciently long that the bight portion protrudes through itsassociated aperture 26.

It is now seen that the angling of the blade or knife 45 about itslongitudinal axis so as to tilt it with respect to the line of blades45, as described above, serves a triple function of: (l) disposing theangled cutting edge 51 of each blade 45 for slicing action with respectto the loops L as opposed to merely a chopping action,ras when thecutting edge is perpendicular to its line of movement; (2) permitting anoverlapping of the cutting edges 51, to thereby prevent the inadvertentwedging of yarns Y between the adjacent blades 45; and, (3) applyinguniform pressure to the angled cutting edge 51 of each blade 45,throughout the length of cutting edge 51.

Still a further advantage is derived from my overlapped bladearrangement in that the biasing of the cutting edges 51 against theshear plate 25 permits a self sharpening action to take place on theedges 51 as they are reciprocated; while, at the same time, providingfor a self equalizing action in that, if one portion or increment of acutting edge 51 is biased more than another portion or incrementthereof, the more biased portion will wea-r more quickly thereby tendingto equalize the pressure on each increment of the edge 51.

It will be obvious to those skilled in the art that many variations maybe made in the embodiments chosen -for the purpose of illustrating thepresent invention without departing from the scope thereof as defined bythe appended claims.

I claim:

1. In atufting machine of the ty-pe having needles which insert yarnscarried thereby through a backing material for forming loops in thebacking material and having a shear plate provided with aperturesthrough which the loops project, the combination therewith of aplurality of blades, each of said blades having a cutting edge at oneend thereof and lateral sides extending away from said cutting edge,means supporting said blades adjacent said shear plate with the cuttingedges of said blades facing in a common direction toward said aperturesand the sides of said blades in mutually overlapping relation, and meansfor moving said blades endwise in said common direction across saidapertures in contact with said shear plate for severing a portion ofsaid loops.

2. In a tufting machine of the type having needles which insert yarnscarried thereby through a backing material from one side thereof forforming loops in the other side of the backing material and having ashear plate provided with apertures through which the loops of aprescribed length project, the combination therewith of a plurality ofblades, means supporting said blades adjacent said shear plate inoverlapping fashion and means for moving said blades across saidapertures for severing a portion of said loops, said blades havingangled cutting edges with the leading portion of the cutting edge of oneblade overlapping the trailing portion of an adjacent cutting edge, eachof said blades being generally flatwise with respect to and tiexedagainst said shear plate for slideably biasing said cutting edgesagainst the outer surface of said shear plate, each of said cuttingedges being beveled so that the cutting portion of each cutting edge isdefined by the junction of the surface of the blade which is adjacentsaid shear plate and the beveled portion of said cutting edge.

3. In a tufting machine of the type having needles which insert yarnscarried thereby through successive portions of a backing material forforming loops of yarns in the backing material and wherein a shear plateis provided with aperture means through which certain of the loopsprotrude as such loops are formed, and wherein an actuating mechanism isprovided adjacent said shear plate for movement toward and away fromsaid aperture means, the combination therewith of a plurality of ilatgenerally rectangular blades carried by said actuating mechanism, saidflat blades protruding from said actuating mechanisms toward saidaperture means, each of said blades having an angled cutting edge remotefrom said actuating mechanism and a relatively short side edge and arelatively long side edge, the edges of said blades being overlappedwith the relatively short side edge of one blade being closer to saidshear plate than its relatively long side edge.

4. In a tuting machine of the type having needles which insert yarnscarried thereby through successive portions of a backing material forforming loops of yarn in the backing material and wherein a shear plateis provided with aperture means through which certain of the loopsprotrude as such loops are formed, and wherein an actuating mechanism isprovided adjacent said shear plate for movement toward and away fromsaid aperture means, the combination therewith a plurality of ilatgenerally rectangular blades carried by said actuating mechanism, saidat blades protruding from said actuating mechanisms toward said aperturemeans, each ot' said blades having an angled cutting edge remote fromsaid actuating mechanism and a relatively short side edge and arelatively long side edge, the edges of said blades being overlappedwith the relatively short side edge of one blade being closer to saidshear plate than its relatively long side edge, the relatively shortside edge of one ot said blades being closer to the shear plate than therelatively long side edge of an adjacent blade, said cutting edge ofeach blade being biased against said shear plate so that the surface ofthe blade adjacent said shear plate is in a convexed condition and thesurface of said blade remote from said shear plate is in a concavedcondition, the cutting edges of said blades being simultaneously movableby said actuating mechanism across said aperture means for severing thebights of said loops as said loops protrude through said aperture means.

5. In a tufting machine of the type having needles which insert yarnscarried thereby through successive portions of a backing material forforming loops of yarn in the backing material and wherein a shear plateis provided with aperture means through which certain of the loopsprotrude as such loops are formed, and wherein an actuating mechanism isprovided adjacent said shear plate for movement toward and away fromsaid aperture means, the combination therewith of a plurality of flatgenerally rectangular blades carried by said actuating mechanism, saidflat blades protruding from said actuating mechanisms toward saidaperture means, each of said blades having an angled cutting edge remotefrom said actuating mechanisms and a relatively short side edge and arelatively long side edge, the edges of said blades being overlappedwith the relatively short side edge of one blade being closer to saidshear plate than its relatively long side edge, the relatively shortside edge of one of said blades being closer to the shear plate than therelatively long side edge of an adjacent blade, said cutting edge ofeach blade being biased against said shear plate so that the surface ofthe blade adjacent said shear plate is in a convexed condition and thesurface of said blade remote from said shear plate is in a concavedcondition, said cutting edge of each blade being beveled to provide acutting portion defined by the beveled surface ot said cutting edge andthe surface of said blade adjacent said shear plate, the cutting edgesof said blades being simultaneously movable by said actuating mechanismacross said aperture means for severing the bights of said loops as saidloops protrude through said aperture means.

6. In a tufting machine of the type having needles which insert yarnscarried thereby through successive portions of a backing material forforming loops of yarn in the backing material and wherein a shear plateis provided with aperture means through which certain of the loopsprotrude as such loops are formed, and wherein an actuating mechanism isprovided adjacent said shear plate for movement toward and away fromsaid aperture means, the combination therewith of a plurality of bladescarried by said actuating mechanism, said blades biased against saidshear plate so that the surface of the blade adjacent said shear plateis in a convexed condition and the surface of said blade remote fromsaid shear plate is in a concaved condition, said blades each having acutting edge beveled to provide a cutting portion defined by the beveledsurface of said cutting edge and the surface of said blade adjacent saidshear plate, the cutting edges of said blades being simultaneouslymovable by said actuating mechanism across said aperture means forsevering the bights of said loops as said loops protrude through saidaperture means.

7. A tufting machine according to claim 1 wherein said cutting edges areinclined relative to the direction of movement of said blades with theleading portion of the cutting edge of one blade overlapping thetrailing portion of an adjacent cutting edge.

8. A tufting machine according to claim 1 wherein said blades are madeof resilient spring material and said blade supporting means retainssaid blades flexed against said shear plate.

References Cited UNITED sTATEs PATENTS 1,970,703 8/1934 Loos i12-792,070,287 2/1937 Loos i12-79 2,356,378 8/1944 Capoiupo 26-7 2,876,5253/1959 Jamey et a1. 28-78 JORDAN FRANKLIN, Primary Examiner.

I. R. BOLER, Assistant Examiner.

1. IN A TUFTING MACHINE OF THE TYPE HAVING NEEDLES WHICH INSERT YARNSCARRIED THEREBY THROUGH A BACKING MATERIAL FOR FORMING LOOPS IN THEBACKING MATERIAL AND HAVING A SHEAR PLATE PROVIDED WITH APERTURESTHROUGH WHICH THE LOOPS PROJECT, THE COMBINATION THEREWITH OF APLURALITY OF BLADES, EACH OF SAID BLADES HAVING A CUTTING EDGE AT ONEEND THEREOF AND LATERAL SIDES EXTENDING AWAY FROM SAID CUTTING EDGE,MEANS SUPPORTING SAID BLADES ADJACENT SAID SHEAR PLATE WITH THE CUTTINGEDGES OF SAID BLADES FACING IN A COMMON DIRECTION TOWARD SAID APERTURESAND THE SIDES OF SAID BLADES IN MUTUALLY OVERLAPPING RELATION, AND MEANSFOR MOVING SAID BLADES ENDWISE IN SAID COMMON DIRECTION ACROSS SAIDAPERTURES IN CONTACT WITH SAID SHEAR PLATE FOR SEVERING A PORTION OFSAID LOOPS.